I have a hard time believing the captain crank was destroyed beyond usability during removal. Far more likely is the bike had an eccentric with a wedge and the shop blew out the wedge threads trying to drive the wedge out by hitting the bolt. It seems like you would hit the wedge bolt like you would to loosen a standard stem. But that will destroy the eccentric. The proper way is actually to remove the bolt and hit the eccentric body away from the wedge with a BFH. http://www.bushnelltandems.com/artic...splitwedge.gif

https://www.rodbikes.com/store/?prod...bottom-bracket